“Blue-green algae” refers to various species of bacteria that produce blue-green colored pigments. They grow in saltwater and some big freshwater lakes. Blue-green algae have been used for food for numerous centuries, in Mexico and some African countries. They have been marketed as a supplement in the US since the late 1970s.

Blue-green algae are consumed by mouth as a source of dietary protein, B-vitamins, and iron. They are also consumed for anemia and to stop unintentional weight loss. Blue-green algae are also used for attention deficit-hyperactivity disorder (ADHD), diabetes, hay fever, stress, fatigue, anxiety, depression, weight loss, and premenstrual syndrome (PMS) and other women’s health issues such as menopause.

Many people use blue-green algae for treating precancerous growths inside the mouth, twitching of the eyelids, boosting the immune system, improving memory, increasing energy and metabolism, improving exercise performance, lowering cholesterol, preventing heart disease, healing wounds, and improving digestion and bowel health. Blue-green algae are also taken by mouth for high blood pressure, HIV/AIDS and HIV-related conditions, cancer, fatty liver disease, hepatitis C, and arsenic poisoning.

Blue-green algae are usually found in tropical or subtropical waters that have a high salt content, but some types grow in large freshwater lakes. The natural color of these algae can give bodies of water a dark-green appearance.

Some blue-green algae products are produced under controlled conditions. Others are grown in a natural setting, where they are more prone to be contaminated by bacteria, liver poisons (microcystins) produced by certain bacteria, and heavy metals. Take only products that have been tested and found free of these contaminants.

You may have been told that blue-green algae are an outstanding source of protein. But, in reality, blue-green algae are no better than milk or meat as a protein source and cost about 30 times as much per gram.

Blue-green Algae Research And Benefits:

•    Seasonal allergies (hayfever). Early research reveals that taking 2 grams per day of blue-green algae by mouth for six months might reduce some allergy symptoms in adults.

•    Insulin resistance due to HIV medication. Early research shows that consuming 19 grams per day of blue-green algae by mouth for two months increases insulin sensitivity in people with insulin resistance due to HIV medication.

•    Arsenic poisoning. Early research shows that taking 250 mg of blue-green algae and 2 mg of zinc by mouth twice daily for 16 weeks decreases arsenic levels and the effects of arsenic on the skin in people living in areas with high arsenic levels in the drinking water.

•    Attention deficit-hyperactivity disorder (ADHD). Early study shows that dissolving 3 mL of a product containing blue-green algae, peony, ashwagandha, gotu kola, bacopa, and lemon balm (Nurture and Clarity, Tree of Healing-LD, Israel) into 50-60 mL of water and drinking three times daily for 4 months improves ADHD in children aged 6 years to 12 years who haven’t taken other treatments for ADHD.

•    Tics or twitching of the eyelids (blepharospasm or Meige syndrome). Early research shows that taking a specific blue-green algae product (Super Blue-Green Algae, Cell Tech, Klamath Falls, OR) at a dose of 1500 mg daily for six months does not reduce eyelid spasms in people with blepharospasm.

•    Diabetes. An early study shows that people with type 2 diabetes who take 1 gram of a blue-green algae product (Multinal, New Ambadi Estate Pvt. Ltd., Madras, India) by mouth twice daily for two months have lower blood sugar levels.

•    Exercise performance. An early study shows that men who jog regularly are able to sprint for longer periods of time before becoming tired when they take 2 grams of blue-green algae three times daily for four weeks.

•    Hepatitis C. Research on the effects of blue-green algae in people with chronic hepatitis C has been inconsistent. One study shows that taking 500 mg of spirulina blue-green algae by mouth three times daily for 6 months results in greater improvements in liver function compared to milk thistle in adults with hepatitis C who were not yet treated or were unresponsive to other treatments. However, another study shows that taking blue-green algae for one month worsens liver function in people with hepatitis C or hepatitis B.

•    HIV/AIDS. Research on the effects of blue-green algae in people with HIV/AIDS has been inconsistent. Some early research shows that taking 5 grams of blue-green algae by mouth daily for 3 months reduces the incidences of infections, stomach and intestinal problems, feelings of tiredness, and breathing problems in patients with HIV/AIDS. However, taking blue-green algae does not appear to improve CD4 cell counts or reduce viral load in HIV patients.

•    High cholesterol. Early research shows that blue-green algae lowers cholesterol in people with normal or slightly elevated cholesterol levels. However, the research findings have been somewhat inconsistent. In some studies, blue-green algae only lower low-density lipoprotein (LDL or “bad”) cholesterol. In other studies, blue-green algae lower total cholesterol and LDL cholesterol, and increase high-density lipoprotein (HDL or “good”) cholesterol.

•    High blood pressure. Early research shows that taking 4.5 grams per day of blue-green algae by mouth for 6 weeks reduces blood pressure in some people with high blood pressure.

•    Long-term fatigue. Early research shows that taking 1 gram per day of blue-green algae by mouth three times daily for 4 weeks does not improve fatigue in adults with long-term complaints of fatigue.

•    Malnutrition. Early research on the use of blue-green algae in combination with other dietary treatments for malnutrition in infants and children shows conflicting results. Weight gain was seen in undernourished children who were given spirulina blue-green algae with a combination of millet, soy and peanut for 8 weeks. However, in another study, children up to 3 years-old who were given 5 grams of blue-green algae daily for 3 months did not gain weight more than those given general treatments to improve nutrition alone.

•    Menopausal symptoms. An early study shows that taking 1.6 grams per day of a blue-green algae product by mouth daily for 8 weeks lowers anxiety and depression in women going through menopause. However, it doesn’t appear to reduce symptoms such as hot flashes.

•    Obesity. Research on the effects of blue-green algae in people who are overweight or obese has been inconsistent. One early study shows that taking a specific blue-green algae product (Multinal, New Ambadi Estate Pvt. Ltd.) at a dose of 1 gram taken two or four times per day by mouth for 3 months slightly improve weight loss in overweight adults. However, another early study shows that taking 2.8 grams of spirulina by mouth three times per day for 4 weeks does not improve weight loss in obese adults who are also following a reduced-calorie diet.

•    Precancerous mouth sores (oral leukoplakia). Early research shows that taking 1 gram of spirulina blue-green algae daily by mouth for 12 months reduces oral leukoplakia in people who chew tobacco.

•    Gum disease (periodontitis). Early research shows that injecting a gel containing blue-green algae into the gums of adults with gum disease improves gum health.

•    Anxiety.

•    As a source of dietary protein, B-vitamins, and iron.

•    Boosting the immune system.

•    Premenstrual syndrome (PMS).

•    Depression.

•    Digestion.

•    Heart disease.

•    Memory.

•    Wound healing.

How does it work?

Blue-green algae have a high protein, iron, and other mineral elements which are absorbed when taken orally. Blue-green algae are being studied for their potential effects on the immune system, swelling (inflammation), and viral infections. (USDA Spirulina Nutrition)

Are there safety concerns?

Blue-green algae products that are free of contaminants, such as liver-damaging substances called microcystins, toxic metals, and harmful bacteria, are POSSIBLY SAFE for most people when used short-term. Doses up to 19 grams per day have been used safely for up to 2 months. Lower doses of 10 grams per day have been used safely for up to 6 months. Side effects are typically light and may include nausea, vomiting, diarrhea, abdominal discomfort, fatigue, headache, and dizziness.

But blue-green algae products that are contaminated are POSSIBLY UNSAFE, especially for children. Children are more sensitive to contaminated blue-green algae products than adults.

Contaminated blue-green algae can cause liver damage, stomach pain, nausea, vomiting, weakness, thirst, rapid heartbeat, shock, and death. Don’t use any blue-green algae product that hasn’t been tested and found free of microcystins and other contamination.

Special precautions & warnings:

Pregnancy and breast-feeding: Not enough is known about the use of blue-green algae during pregnancy and breast-feeding. Stay on the safe side and avoid use.

“Auto-immune diseases” such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), rheumatoid arthritis (RA), pemphigus vulgaris (a skin condition), and others: Blue-green algae might cause the immune system to become more active, and this could increase the symptoms of auto-immune diseases. If you have one of these conditions, it’s best to avoid using blue-green algae.


Bleeding disorders: Blue-green algae might slow blood clotting and increase the risk of bruising and bleeding in people with bleeding disorders.


Phenylketonuria: The spirulina species of blue-green algae contains the chemical phenylalanine. This might make phenylketonuria worse. Avoid Spirulina species blue-green algae products if you have phenylketonuria.

What dose is used?

The appropriate dose of blue-green algae depends on numerous factors such as the user’s age, health, and several other conditions. At this time there is not complete scientific information to determine an appropriate range of doses for blue-green algae. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and ask your pharmacist or physician or other healthcare professional before using.

(Full Research Source)